Newton Developer Technical Information: Newton Programmer's Guide: 2.1 OS Addendum /

Chapter 2 - Newton Works Draw Application / Draw Application Reference

Proto / protoDrawTool

AdjustBounds

protoDrawTool:AdjustBounds(shape, style, left, top, right, bottom, constrain)

Called to limit the bounds of the object as the user is dragging out a new bounding box or resizing an existing object.

shape

Either a graphic object, or nil if a new object is being created and dragARectangle is set to true.

style

The current user defaults for penSize, penPattern, fillPattern, and font.

left

The x-coordinate of the start point of the rectangle the user dragged with this tool.

top

The y-coordinate of the start point of the rectangle the user dragged with this tool.

right

The x-coordinate of the end point of the rectangle the user dragged with this tool.

bottom

The y-coordinate of the start point of the rectangle the user dragged with this tool.

constrain

The value true indicates that the shift key is pressed.

return value

A bounds frame.

DISCUSSION

The default version of this method limits the bounding box to always be square when constrain is true. If you override this method, you should do something similar.

SPECIAL CONSIDERATIONS

If the user drags up and to the left, the values passed as the right and bottom arguments can be less than those passed as the left and top arguments. The left slot in bounds frame you return should be Min(left, right), the top slot should be Min(top, bottom), and so on.